The following discussion of the background to the invention is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge of the person skilled in the art in any jurisdiction as at the priority date of the invention.
Switched mode power supplies are often utilized for driving one or more applications. In particular, Light Emitting Diodes (LEDs) lamps are often driven by controller circuits. As LEDs are sensitive to current and voltage fluctuations, one of the most important objectives for LED controller circuits is to provide appropriate current to drive the LEDs under supply voltage or load variations.
Many LED switched-mode based controllers involve the use of electronic switches such as MOSFET as a means for regulating the current input to the LEDs. As such, the control of the frequency and on/off time for switching is an important parameter to consider in all switched-mode based controllers.
There exists an on-going need to improve switching control of LED drivers to achieve one or more of the following:—
i. reduction in overall component count such as capacitor(s);
ii. reduction in form factor of each component; and/or
iii. proper over-voltage/short circuit protection.
In addition, there also exists a need to move away from secondary voltage feedback type controls as it places an undesirable burden on the transformer or inductive transfer elements.
It is thus an object of the invention to overcome, or at least ameliorate in part, one or more of the aforementioned problems.